CVE-2021-21698: Subversion Path Traversal Vulnerability

MODERATE
Advisory Identifier: GHSA-q58j-fhj7-j6fg
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CVSS 6.5
CWE-22
Published
Advisory Summary

CVE-2021-21698 is a MODERATE (CVSS 6.5) path traversal vulnerability (CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')) affecting Subversion libraries in the Maven ecosystem. The issue involves path traversal vulnerability in jenkins subversion plugin allows reading arbitrary files. Remediation is available by upgrading affected packages to version 2.15.1.

CVE-2021-21698 at a Glance

CVE Identifier CVE-2021-21698
GHSA Identifier GHSA-q58j-fhj7-j6fg
Severity MODERATE
CVSS v3.1 Base Score 6.5
CWE Classification CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Affected Product Subversion
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 6.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity None (I:N)
Availability None (A:N)

How to Fix CVE-2021-21698

To remediate this vulnerability, upgrade all affected Subversion dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

org.jenkins-ci.plugins:subversion fixed: 2.15.1 
<dependency>
    <groupId>org.jenkins-ci.plugins</groupId>
    <artifactId>subversion</artifactId>
    <version>2.15.1</version>
</dependency>
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree -Dincludes=org.jenkins-ci.plugins

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2021-21698, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=org.jenkins-ci.plugins

Analyze the terminal output to locate any version of Subversion in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.15.1), your application is affected.

Note: The mvn dependency:tree -Dincludes=org.jenkins-ci.plugins command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal'), where the product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. In Subversion, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

Subversion Plugin 2.15.0 and earlier does not restrict the name of a file when looking up a subversion key file on the controller from an agent. This allows attackers able to control agent processes to read arbitrary files on the Jenkins controller file system. Subversion Plugin 2.15.1 checks for the presence of and prohibits directory separator characters as part of the file name, restricting it to the intended directory.

CVE-2021-21698 Affected Subversion Versions

1 component(s)
Fixed Versions:
2.15.1
Product / Package Ecosystem Affected Versions Fixed Version
org.jenkins-ci.plugins:subversion
maven/org.jenkins-ci.plugins/subversion
Maven
< 2.15.1
2.15.1

References

NVD — CVE-2021-21698 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-21698
Security Fix Commit FIX COMMIT
https://github.com/jenkinsci/subversion-plugin/commit/7d1525edea6641a2febd3f7deeac55c0a89b0d7e
Subversion Source Repository REPOSITORY
https://github.com/jenkinsci/subversion-plugin
Subversion Security Information SECURITY
https://www.jenkins.io/security/advisory/2021-11-04/#SECURITY-2506
Subversion Security Information SECURITY
http://www.openwall.com/lists/oss-security/2021/11/04/3

Frequently Asked Questions

What is CVE-2021-21698?
CVE-2021-21698 is a security vulnerability in Subversion involving Path traversal vulnerability in Jenkins Subversion Plugin allows reading arbitrary files under CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal').
Which Subversion versions are affected?
Affected versions include releases prior to 2.15.1 across affected packages: org.jenkins-ci.plugins:subversion.
What version fixes CVE-2021-21698?
Upgrading to 2.15.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is subversion affected?
Yes, org.jenkins-ci.plugins:subversion is affected in releases prior to 2.15.1. Upgrade your dependency to 2.15.1 or later.
What is the CVSS score of CVE-2021-21698?
CVE-2021-21698 has a CVSS v3.1 base score of 6.5 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.
What CWE is associated with CVE-2021-21698?
CVE-2021-21698 is classified under CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') (The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.).
How can I check Maven dependencies for CVE-2021-21698?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=org.jenkins-ci.plugins'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-q58j-fhj7-j6fg",
  "modified" : "2022-12-16T22:58:21Z",
  "published" : "2022-05-24T19:19:43Z",
  "aliases" : [ "CVE-2021-21698" ],
  "summary" : "Path traversal vulnerability in Jenkins Subversion Plugin allows reading arbitrary files",
  "details" : "Subversion Plugin 2.15.0 and earlier does not restrict the name of a file when looking up a subversion key file on the controller from an agent.\n\nThis allows attackers able to control agent processes to read arbitrary files on the Jenkins controller file system.\n\nSubversion Plugin 2.15.1 checks for the presence of and prohibits directory separator characters as part of the file name, restricting it to the intended directory.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.jenkins-ci.plugins:subversion"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.15.1"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 2.15.0"
    }
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-21698"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/jenkinsci/subversion-plugin/commit/7d1525edea6641a2febd3f7deeac55c0a89b0d7e"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/jenkinsci/subversion-plugin"
  }, {
    "type" : "WEB",
    "url" : "https://www.jenkins.io/security/advisory/2021-11-04/#SECURITY-2506"
  }, {
    "type" : "WEB",
    "url" : "http://www.openwall.com/lists/oss-security/2021/11/04/3"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-22" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2022-12-16T22:58:21Z",
    "nvd_published_at" : "2021-11-04T17:15:00Z"
  }
}